Swanton confirmed with Channel 6 that a female driver and a "child or pre-teen" died in one of the two passenger vehicles involved in addition to the truck driver who was pronounced dead earlier Tuesday afternoon.

Police said northbound lanes will remain closed for up to five more hours. Traffic is reportedly backed up to the Bruceville-Eddy area and possibly further, according to Waco Police Sgt. Patrick Swanton. He warns travelers heading north towards Waco may want to make overnight plans in areas south of Waco.

Waco PD tried to re-open the Valley Mills overpass, but chunks of concrete started falling off the structure as cars crossed over and police re-closed the overpass.

TxDOT later determined that the flyover leading traffic from S. Valley Mills Drive onto the northbound lanes of I-35 had been structurally damaged in this afternoons crash and will remain closed until additional inspections can be conducted tomorrow. This will interrupt traffic flow in the morning, so police advise commuters to take alternate routes.

Robinson PD reports that Wal-Mart has donated water to Victorious Life Church, and the church has opened its doors to provide food and water to stranded motorists along I-35. The church is located on the northbound side of I-35 near Waco Memorial Cemetery. The address for the church is 7459 N. Interstate Highway 35, Waco, TX.

Robinson Police Department is also on foot providing water and offering gas to stranded motorists.

Any questions or specific requests can be addressed to Robinson Police Department at (254)662-0525.

Firefighters responded to a deadly, fiery multi-vehicle crash on I-35 underneath the South Valley Mills overpass in Waco Tuesday afternoon.

In a press conference Tuesday afternoon, Waco Police Sergeant Patrick Swanton said there were at least two fatalities in the crash, which involved four 18-wheelers with trailers and two passenger vehicles. Swanton said a passenger vehicle under one of the semis was too mangled to accurately determine how many deceased victims were inside.

One of two confirmed deceased victims was one of the 18-wheeler drivers, while the second was in one of the passenger vehicles, Swanton said.

PHOTOS: Semi fire on I-35 in Waco

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Fire officials said 13 units and 40 first responders were dispatched to the scene. One firefighter suffered an injury. Neither his condition nor the circumstances surrounding his injury were immediately released by first responders.

All lanes were shut down on the northbound side of the interstate, and one lane was closed on the southbound side, according to TxDOT. Waco Police said traffic was being diverted around the city -- with northbound traffic being rerouted at exit 339 and southbound traffic being diverted at the Bellmead city limits.